Question

como resolvo essa conta??

Answer 1

625+50b+b²-625+50b-b²
50b+50b:1000
100b:1000
b:10 
letra E

Answer 2

(a+b)²-(a-b)² = 1000
a²+2ab+b² -(a²-2ab+b²)=1000
a²+2ab+b² - a²+2ab-b² = 1000
4ab = 1000
 4.25.b = 1000
 100b = 1000 ⇔ b = 10
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$\frac{x^2-y^2}{x^2+2y+y^2}=$

$\frac{(x+y).(x-y)}{(x+y)^2}= \frac{x-y}{x+y}$

$\frac{26-24}{26+24}= \frac{2}{50}= \frac{1}{25}=0,04$